Fishing reels conventionally include a drag device as disclosed in, e.g., Japanese Patent Application Publication No. H10-136853 (the “'853 Publication”). When a fish is caught on a tackle, the drag device applies a braking force to a fishing line being pulled out. The spinning reel as disclosed in the '853 Publication is configured such that a drag knob can be adjusted to apply a desired braking force to the rotation of a spool rotatably retained on a spool shaft.
The drag device described above is included in various fishing reels such as spinning reels, double bearing reels, and single bearing reels. Spinning reels include front drag type and rear drag type. Typically, spinning reels include a plurality of brake members (lining washers, drag washers) adjacent to and in surface contact with each other so as to produce a braking force between a spool shaft and a spool.
The lining washers are formed of, e.g., a synthetic resin including felt, pulp, or reinforcement fiber or a punching resin; and the drag washers (mating members mating with the lining washers) are formed of a highly resistant metallic material and unrotatably fixed on a spool or a spool shaft. The lining washers (which may be constituted by multiple plates) are disposed to be retained between drag washers and are typically greased for smooth braking.
Such a drag device allows a user to adjust the drag force desirably in actual fishing. That is, the drag force can be increased by tightening a drag adjustment knob to produce a larger surface pressure on the lining washers, and the drag force can be reduced by loosening the drag adjustment knob to produce a smaller surface pressure on the lining washer.
As described above, the drag force varies in accordance with the surface pressure between the drag washers and the lining washers, or the frictional force therebetween. This frictional force serves as resistance and produces a drag force, which causes heat and wear between the drag washers and the lining washers. Such an effect can be suppressed by greasing the lining washers as described above.
Conventional drag devices suffer from an instable drag force during drag operation or a high impact upon switching from a static friction state to a dynamic friction state under a drag force. These problems are caused by several factors; and one of them may be an effect of the grease applied to the lining washers. The grease applied to the lining washers forms an oil film on the surface thereof. Conventionally, the grease cannot form a stable film between the lining washers and the drag washers, which causes the above problems. In particular, a large drag force produces a large surface pressure on the lining washers to break the oil film or causes the grease to penetrate a part of the lining washers, such that the surfaces of the lining washers are unevenly greased to have an instable oil film. Accordingly, when a rotational force is applied, the oil film may be broken by a shear force at portions having small thicknesses, thereby destabilizing the drag performance.